Does Current Affect The Amount Of Copper Transferred During Electrolysis With Copper Electrodes In A Copper Sulphate Solution?

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Does Current Affect The Amount Of Copper Transferred During Electrolysis With Copper Electrodes In A Copper Sulphate Solution? By Will McEwan Aim To investigate how the amount of copper transferred during electrolysis is influenced by the current. Prediction I predict that with a greater current, more copper will be transferred. They will be directly proportional. Hypothesis The Copper atoms are using the electrolyte (copper sulphate) to transfer themselves between the two electrodes. If the current increase then the amount of copper atoms crossing between the electrodes also increases, thus increasing mass of copper transferred. Apparatus Ammeter Beaker Cell Pack Stopwatch Copper Sulphate Solution Copper Electrodes Crocodile Clips Scales Propanone Iron Wool Variable Resistor Wires Diagram Method * Take the copper electrodes and clean them with iron wool (to remove impurities on surface and aid electrolysis), taking care not to get splinters of iron into fingers. ...read more.

However, my preliminary results fully support it. In theory my prediction is right, but in practice it is near impossible to give supporting evidence. Evaluation My experiment was performed under very basic conditions. From the preliminary work I can see that it is not my prediction that is wrong. I believe that given perfect lab conditions and enough time I could prove my prediction right. In my experiment I lost a lot of copper in the electrolyte. I could improve my experiment by filtering the electrolyte each time and weighing the filtrate with the paddles this would prevent loss of mass. When drying the paddles I sometimes oxidised the copper and this added mass. In future the paddles could be dried by different means such as a hairdryer on a very low heat. It took about 30 seconds to set the right current, as this is 10% of the total time this could have an effect on the amount of copper that was transferred. To overcome this problem, a digital resistor could be used that automatically sets the amount of current. ...read more.

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it can be seen that my initial prediction was correct. As the concentration increases, so does the current. This is due to two things that happen as the electrolysis occurs. First, bubbles form at the anode, meaning that the oxygen gas is being produced and the ions are being transferred.

The graph of the results of the experiment when compare with the one of the actual mass it looks quite the same but some are anomalous, the anomalous results were circled in the graph to distinguish from the other values.

In the electrolyte these charged particles are mobile ions. At the electrodes electrons are given to the cat ions cathode (-), and are released at the anode (+), so the current flows. Therefore species are gaining electrons at the cathode, and so being oxidised, whilst electrons are taken away at the cathode (reduction).

So if the current is doubled, then the mass of copper collected will also double and if the current is tripled then the mass will also triple. We can work out the approximate mass of copper collected at the end of the reaction with Faraday's Law.

holder with crocodile clips An electronic balance Propanone Distilled water Ammonia Solution Tissue to wipe electrodes with A piece of emery paper A wooden mat DiagrMethod The apparatus was set up as shown in the diagram above. One of the two copper electrodes is cleaned with emery paper on a

The copper ions will be attracted to the negative electrode where they can be weighed. I predict that copper will migrate from the anode to the cathode. The copper sulphate will be ionised which will result in the copper and sulphate separating: CuSO4(aq)